12 Slit Showerhead Perc Pre CoolerThis is another heavy weight clear glass pre cooler from Black Leafs range. Warning, this pre cooler is very heavy and will only fit safely on a heavy duty, large bong. The special part about this pre cooler is the 12 slit showerhead perc that sits in the main section for optimal smoke diffusion. The male and female ground joints are 18. 8mm and this pre cooler stands 130mm tall. The male joint points is fixed at an angle for placement onto your bong.